usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespaceConsoleApplication2{classProgram{staticvoidMain(string[]args){Moneym=newMoney();m.Amount=30.00m;Console.WriteLine(m.ToString());//输出$:30.00//使用扩展方法m.AddToMoney(1.00m);Console.WriteLine(m.ToString());//输出$:31.00Console.ReadKey();}}publicclassMoney{privatedecimalamount;publicdecimalAmount{set{amount=value;}get{returnamount;}}publicoverridestringToString()//重写ToString方法{return"$:"+amount.ToString();}}//扩展方法publicstaticclassMoneyExtension{//thisMoneym扩展方法的规则，告诉编译器这个方法是Money类型的一部分publicstaticvoidAddToMoney(thisMoneym,decimald){m.Amount+=d;}}}